Quick Outboard Question

[dave7]

I found this on an outboard maintenance page:

If you see black "oil" dripping out of the propeller hub:
that's not oil, it's carbon coming out of the exhaust. Use a de-carbonizer (AKA engine cleaner).

Is this right? Just want a confirmation from a second source...
I've noticed that my motor has a little bit of oily *really dark* stuff acumulated on the skeg (I think that's what the bottom-most part is called).

Thanks- dave

[tin can]

I would agree that it COULD be, and most likely is carbon buildup. I would check the lower unit grease first, to eliminate a lower unit problem.

In the late 1980's, and early 1990's, OMC had a Shrader valve on the primer. They manufactured an aerisol can of engine cleaner that screwed onto the valve. You ran the outboard with the can of cleaner attached. If the engine was carboned up, all manner of black crud came out of the exhaust.

All of the outboard manufacturers have a carbon reduction product. Most are fuel addatives. These were developed for the simple, old fashioned, mixed fuel, carbeurated 2 strokes. I don't have any idea what is reccommended for the EFI, or DFI motors.

[dave7]

Thanks!

Um, how do I check the lower unit grease?

[tin can]

Thanks!

Um, how do I check the lower unit grease?

As you have recently purchased a used rig, I would recommend changing the lower unit grease. If you look on the starboard side of your Johnson lower unit, You'll see a large screw head on the bottom of the gear case, near the leading edge. You'll see another one like it just below the cavitation plate. Lhe lower screw is the drain/fill hole. The upper screw is the vent/overflow hole. I would suggest you stop by Wal-Mart and pick up a lower unit grease kit. The kit consists of a quart of lower unit grease, and a pump to put it in with.

Put a clean pan under your lower unit with the motor in the down position. Remove both screws. The grease will drain. The grease should not have any indication of water intrusion. You're going to find a few metal filings on the magnet made to the lower screw. This is normal. If you find small metal chunks, or the grease comes out very dark and clumpy, you need to take it to Wavel.

Lets assume the grease looks OK. Screw the fitting on the pump into the bottom hole, under the gearcase. With the pump in the grease bottle, pump away, until grease comes out the top hole. Insert the top screw. Remove the pump from the bottom hole and quickly insert the lower screw. You're done.

[mjsigns]

Dave- if your lower unit oil looks anything like this, you have water intrusion and will need to have your lower unit seals replaced.

[dave7]

Thanks guys! Great description TC. I'll go ahead and change that out. Sounds like a new project and yet another trip to Wallyworld. How often would you change this oil? Yearly... ?

I take it that Lower Unit Grease / Oil is pretty standard across the board? My Johnson shouldn't have require anything special, right?

[tin can]

I change my lower unit grease yearly. I've been using Pennzoil, from Wal-Mart. It works fine. Your Johnson should be fine with Penzoil.

[chugbug]

Get some of the stuff on your finger and smell it. You will know if it is gear lube. If it is gear lube, don't bother changing it as the new stuff will leak out too. You can take it to a marina and they can pressure test the foot. It shouldn't cost that much.

[pennfish]

Dave7, buy the lower unit kit like TC says and get another bottle because the pumper dosent like to scavenge all of the oil from the first bottle and your unit wont be full, also when the oil is almost empty air will want to pump in and that needs to be avoided. If thet black stuff wants to stain or is hard to get off your hands especially fingerprints its most likely carbon or really coked or burned oil and fuel additives being washed from the exhaust transfer tube below the engine. You can try cleaning with chemicals or additives or leave it alone and just go fish. Also all engines Ive seen with this drip are engines where the operator mixes the fuel/oil,just remember MORE OIL IS NOT BETTER 50:1= 2.6oz per gal no more no less. Boat ownership what an adventure

[GT Fisherman]

My vent / overflow screw is stuck. Anybody know a good way to free it? I am afraid I might strip the slot.

[tin can]

My vent / overflow screw is stuck. Anybody know a good way to free it? I am afraid I might strip the slot.

Manual impact driver................CAREFULLY!